Thinking about building a class-D amp

[Shovel_Knight]

I'm thinking about building a class D amp, and would like to use this thread as a means of collecting various bits of info in one place and hopefully fostering useful discussion :-)

We have a quiet time at work right now, so I spent the last week reading diyaudio.com and figuring out what class-D boards/modules would be most appropriate for my needs.

What I want in an amplifier:


audiophile quality;
enough power to drive my current speakers (Usher S520; their sensitivity is just 84.5 dB and apparently they need quite a bit of juice to make them sing);
reasonable requirements in terms of power consumption / heatsinks / size and weight;
it should be relatively straightforward to hook up and configure.


I think the following three options (mostly) meet my needs:

1. Eastern Audio Technology (Hifimediy) T4: https://hifimediy.com/amplifiers/diy-amplifiers/T4-mundorf-amplifier

This board is based on TK2050/STA516 combo.

Pros:


very well-reviewed;
uses high quality components (capacitors, inductors, etc);
this board is basically self-contained and only a handful of components are needed to build a functional amplifier (a case, a transformer, connectors and wiring).


What I don't like about this board is the lack of info and technical documentation. For example, the manufacturer states that it provides 2x180W @ 8 Ohm, but doesn't provide THD at full power. I suspect that the rated output power is at 10% THD. It means that it probably outputs about 50-70 Wpc while keeping distortion reasonable.

2. Connex IRS2092 Stereo: http://connexelectronic.com/product/irs2092-stereo-amplifier/

This board is based on the IRS2092 controller chip and IR power MOSFETs.

Pros:


well-reviewed;
uses high quality components;
provides all the power I will ever need;
very low parts count if used with its matching power supply;
excellent documentation;
best in class protection against fault conditions if used with its matching power supply.


However, there are some things that I don't like about this board. First of all, I'm a bit suspicious about IRS2092 which was initially pitched for PA and automotive applications. On this particular board the output filter, apparently, is not included in the feedback loop, which means that some loads could interact with the filter and adversely affect the sound. The input impedance is very low, so a buffer is needed to provide maximum compatibility with different sources.

3. Hypex UcD180HG-HxR: https://www.diyclassd.com/product/ucd180hg-with-hxr/5

This board is produced by Hypex and uses their proprietary technology. Two boards are needed to build a stereo amp.

Pros:

widely considered to be among the best class-D amps available at the moment;
uses high-quality components;
low parts count if used with its matching power supply;
excellent protection if used with its matching power supply;
balanced input;
excellent documentation.


What I don't like about this board: rated power output at 8 Ohm is 120 W at 1% THD and just 60 W at 0.1% THD (similar to Hifimediy T4). Expensive. No single-ended inputs.


At this point I'm inclined to go with the Hypex simply because it's guaranteed to be good, even if the resulting amplifier would be rather expensive.

[Sherwood]

Have a look at this new product.

http://www.nuprimeaudio.com/product/sta-6/?v=79cba1185463

I have a pair of the more powerful STA-9 which output almost 300w in bridged mode. They are exceptional for the price. I think that either one STA-9 or a pair of STA-6 as monoblocks would suit you well, budget permitting.

Geoff

[Shovel_Knight]

Thanks, I know about NuPrime products and actually used IDA-8 in my home system before moving to Ireland.

Are there any European dealers? I can’t find their stuff for sale anywhere.

And also building something with my own hands is better for my soul... :)

[Sherwood]

Thanks, I know about NuPrime products and actually used IDA-8 in my home system before moving to Ireland.

Are there any European dealers? I can’t find their stuff for sale anywhere.

And also building something with my own hands is better for my soul... :)

Their website lists several European dealers under where to buy section.

Geoff

[Shovel_Knight]

Somehow I’m not too keen on ordering from Romania or Italy, but I will keep this NuPrime amp in mind in case this DIY project turns out to be too expensive (my DIY projects sometimes can spiral out of control in terms of expenses :D).

In the meantime I’d like to think about power requirements and heat dissipation of my DIY project.

The Connex IRS2092 power amp is likely to be the most power hungry of aforementioned options. It outputs 200 Wpc at 4 Ohm or 105 Wpc at 8 Ohm. Efficiency at full output is 92%, so worst case power consumption driving a pair of 4 Ohm speakers will be roughly 435 W. Worst case heat dissipation is going to be about 35 W and the onboard heatsink should take care of it nicely.

A pair of Hypex UcD180 will output 180 Wpc max with 90% efficiency, worst case power consumption is going to be 396 W and worse case heat dissipation is going to be 36 W or 18 W per module. If I use an aluminium case, I can bolt the modules to side panels and it will be enough to cool them efficiently.

[Sherwood]

Somehow I’m not too keen on ordering from Romania or Italy, but I will keep this NuPrime amp in mind in case this DIY project turns out to be too expensive (my DIY projects sometimes can spiral out of control in terms of expenses :D).

In the meantime I’d like to think about power requirements and heat dissipation of my DIY project.

The Connex IRS2092 power amp is likely to be the most power hungry of aforementioned options. It outputs 200 Wpc at 4 Ohm or 105 Wpc at 8 Ohm. Efficiency at full output is 92%, so worst case power consumption driving a pair of 4 Ohm speakers will be roughly 435 W. Worst case heat dissipation is going to be about 35 W and the onboard heatsink should take care of it nicely.

A pair of Hypex UcD180 will output 180 Wpc max with 90% efficiency, worst case power consumption is going to be 396 W and worse case heat dissipation is going to be 36 W or 18 W per module. If I use an aluminium case, I can bolt the modules to side panels and it will be enough to cool them efficiently.

Why would you want to buy from those countries rather than Belgium, France, Germany or the Netherlands?

Geoff

[Shovel_Knight]

Ideally, I’d like to buy from Ireland or U.K., but couldn’t find it for sale here ¯\_(ツ)_/¯

[Sherwood]

Ideally, I’d like to buy from Ireland or U.K., but couldn’t find it for sale here ¯\_(ツ)_/¯

True, not yet. I just wondered why you referenced those unlikely countries other than nearer ones.

Geoff

[r100]

I'm looking forward to your build :)

I have a penchant towards the Connex products. I've put together some IRS2092 amps with good results. The latest one was a LJM L15 (with the old capacitors). They are pretty cheap, so I gave them a try. I preferred running them with a linear PSU as opposed to a SMPS.

What I like with Connex (as with Hypex) is that all the components (SMPS/AMP) are meant to work together. I also think that the UcD / NCore amps are overpriced for the extra 0.1% in SQ you aparently get. I had a UcD with the regulators - but I couldn't say if it was that was much better than a well power-supplied IRS2092). What was obvious was the difference in price !

Good luck with the build.

[Shovel_Knight]

Thanks! I hope it will be worth it :-)

Next step is making the BOMs and calculating possible expenses.

[r100]

:idea:
I just saw that audiophonics are also selling Connex (and Hypex) products from France...

Link (https://www.audiophonics.fr/en/amplifier-boards/irs2092-stereo-class-d-amplifier-2x-400w-4-ohms-p-9760.html)

[Shovel_Knight]

Yes, that’s why I’m inclined to go with them (to avoid paying customs fees and handling charges) :-)

Although the main Hypex we shop is in the Netherlands, so no customs fees when ordering from there as well.

[Shovel_Knight]

A quick update: I'm currently working on calculating costs for my three primary options, and so far it doesn't look great. The least expensive option (Hifimediy T4) is about 250 euros and the most expensive one (Hypex) is more than 450 :scratch: The NuPrime amp is looking really attractive now :D

Maybe a DIY pre would be a more cost effective solution.

[Sherwood]

A quick update: I'm currently working on calculating costs for my three primary options, and so far it doesn't look great. The least expensive option (Hifimediy T4) is about 250 euros and the most expensive one (Hypex) is more than 450 :scratch: The NuPrime amp is looking really attractive now :D

Maybe a DIY pre would be a more cost effective solution.

If you went for a Nuprime you might find one STA-9 sufficient rather than two STA-6 in mono mode. Having said that, running the STA-9's in bridged mode does more than just increase the power output. For whatever reason, the sound becomes more valve like and everything else seems to come into sharper focus. I have no technical explanation for this and I am not the only one to comment on it. I am guessing that the same effect would be evident with a pair of STA-6's.

Geoff

[montesquieu]

Thanks, I know about NuPrime products and actually used IDA-8 in my home system before moving to Ireland.

Are there any European dealers? I can’t find their stuff for sale anywhere.

And also building something with my own hands is better for my soul... :)

I had a bad experience with the Dutch/Belgian dealer and an STA-9, so much so that I asked Jason Lim the founder of the company to step in. (It's not a bad amp though - not quite there with a top valve amp but well ahead of an ordinary one).

I tried contacting the French dealer but got no-response (he's in Avignon, annoyingly I had been there the week before I tried to get in contact).

I believe there is a NuPrime dealer with a good reputation operating in the Nordics (Norway I think) but I'd kind of lost interest by that point. Though I plan to try and hear the ST-10 next time I'm in Taiwan (where they are built, just east of Taipei). I saw the kit at the Munich show last year, but annoyingly, though they had a presence there and I met Jason Lim himself, they didn't have the ST-10 on demo, which was pain. Apparently in the last month or so, Nuprime released ST-10 monoblocks which to me are really interesting.

Not sure how much you'd be building yourself with a class D amp anyway the technology is pretty much sealed up you'd just be connecting ready-made boards up.

[Sherwood]

I had a bad experience with the Dutch/Belgian dealer and an STA-9, so much so that I asked Jason Lim the founder of the company to step in. (It's not a bad amp though - not quite there with a top valve amp but well ahead of an ordinary one).

I tried contacting the French dealer but got no-response (he's in Avignon, annoyingly I had been there the week before I tried to get in contact).

I believe there is a NuPrime dealer with a good reputation operating in the Nordics (Norway I think) but I'd kind of lost interest by that point. Though I plan to try and hear the ST-10 next time I'm in Taiwan (where they are built, just east of Taipei). I saw the kit at the Munich show last year, but annoyingly, though they had a presence there and I met Jason Lim himself, they didn't have the ST-10 on demo, which was pain. Apparently in the last month or so, Nuprime released ST-10 monoblocks which to me are really interesting.

Not sure how much you'd be building yourself with a class D amp anyway the technology is pretty much sealed up you'd just be connecting ready-made boards up.

I actually bought my Nuprimes direct from Jason Lim. Shipping was a nominal rate and directly from the Taiwan factory. IIRC the price was lower (I was offered a discount as a previous Nuforce customer).

Do bear in mind though the improvements brought about by bridging that I mentioned.

Geoff

[Shovel_Knight]

Not sure how much you'd be building yourself with a class D amp anyway the technology is pretty much sealed up you'd just be connecting ready-made boards up.

But at least I'd get to drill holes in the enclosure :D

[Shovel_Knight]

I actually bought my Nuprimes direct from Jason Lim. Shipping was a nominal rate and directly from the Taiwan factory. IIRC the price was lower (I was offered a discount as a previous Nuforce customer).

My experience with NuPrime has been a bit disappointing, to be honest. The products are great, no doubt (as I have mentioned, I used IDA-8 in my own system). But at one point I wanted to buy their HPA-9 headphone amp and contacted their customer support to ask a question about one feature that wasn't explained in the manual. They were not familiar with the product and forwarded my message to Jason Lim. After that, I never heard back from them.

[montesquieu]

But at least I'd get to drill holes in the enclosure :D

Hope you are better at drilling holes than I am!

[Sherwood]

My experience with NuPrime has been a bit disappointing, to be honest. The products are great, no doubt (as I have mentioned, I used IDA-8 in my own system). But at one point I wanted to buy their HPA-9 headphone amp and contacted their customer support to ask a question about one feature that wasn't explained in the manual. They were not familiar with the product and forwarded my message to Jason Lim. After that, I never heard back from them.

My experience was very different. Rapid and detailed response to questions and follow up. Maybe we caught them on good and bad days respectively! I also have an earlier Nuforce product, a DDA-100 integrated digital amp. This is currently serving as the central part of my lounge multimedia system. For the price it is fantastic and to be honest a bit wasted in a multimedia system. I may be parting with it when I go back back overseas shortly.

Geoff

[daddydj]

This amp module has quite a buzz about it....
http://store3.sure-electronics.com/2-x-400-watt-class-d-audio-amplifier-board-compact-t-amp

On one DIY site (I cant remember which) it knocked the top of the line Hypex Module of the top spot.
I will try and find the original thread.

[Shovel_Knight]

This amp module has quite a buzz about it....
http://store3.sure-electronics.com/2-x-400-watt-class-d-audio-amplifier-board-compact-t-amp

On one DIY site (I cant remember which) it knocked the top of the line Hypex Module of the top spot.
I will try and find the original thread.

I’ve seen the thread you’re talking about. But I’m generally wary about generic Chinese boards.

[daddydj]

They are pretty much all made in China

[daddydj]

This was his the list in order of preference, but now he says the Sure is on top.
Obviously this is just one builders views but there seems to be a lot of support for the Sure.

1. Hypex UcD2K Click the image to open in full size. ( Absolute Reference ).
2. Abletec ALC0300-1300 Click the image to open in full size. ( sound-quality wise very close to UcD2K ).
3. Hypex NC-400 Click the image to open in full size. ( Price / Performance-ratio ).
4. Abletec ALC1000-1300 Click the image to open in full size. Click the image to open in full size. ( extremley dynamic, might therefore lack long-term enjoyability on certain speakers ).
5. Connexelectronic CxD500 / SMPS600RE Click the image to open in full size.
6. L-15/25D Click the image to open in full size. ( only if speaker matches ).
7. Hypex UcD180 HG Click the image to open in full size.
8. Connexelectronic IRS2092 (500 + 700 Watt Stereo-Module).
9. Connexelectronic Tripath TA3020 / SMPS1000A Click the image to open in full size. ( unobtrusive ).
10. Hypex UcD400 HxR Click the image to open in full size. ( never really could convinve me ).
11. Hifimediy T2 Click the image to open in full size. ( good, well-sounding and inexpensive entry-level amp )
99. Hifimediy T3S Click the image to open in full size. ( absolutely not noteworthy ).

[Shovel_Knight]

They are pretty much all made in China

This is true, but not all Chinese wares are created equal. For example, Hifimediy and Connex use high quality parts in their modules, but when I look at this Sure board, the first thing I see is a set of noname electrolytic capacitors.

[Shovel_Knight]

This was his the list in order of preference, but now he says the Sure is on top.
Obviously this is just one builders views but there seems to be a lot of support for the Sure.

1. Hypex UcD2K Click the image to open in full size. ( Absolute Reference ).
2. Abletec ALC0300-1300 Click the image to open in full size. ( sound-quality wise very close to UcD2K ).
3. Hypex NC-400 Click the image to open in full size. ( Price / Performance-ratio ).
4. Abletec ALC1000-1300 Click the image to open in full size. Click the image to open in full size. ( extremley dynamic, might therefore lack long-term enjoyability on certain speakers ).
5. Connexelectronic CxD500 / SMPS600RE Click the image to open in full size.
6. L-15/25D Click the image to open in full size. ( only if speaker matches ).
7. Hypex UcD180 HG Click the image to open in full size.
8. Connexelectronic IRS2092 (500 + 700 Watt Stereo-Module).
9. Connexelectronic Tripath TA3020 / SMPS1000A Click the image to open in full size. ( unobtrusive ).
10. Hypex UcD400 HxR Click the image to open in full size. ( never really could convinve me ).
11. Hifimediy T2 Click the image to open in full size. ( good, well-sounding and inexpensive entry-level amp )
99. Hifimediy T3S Click the image to open in full size. ( absolutely not noteworthy ).

By the way, I’m very interested as to where this guy got his Abletec/Anaview modules. I haven’t been able to find them for sale anywhere.

[Qwin]

I've bought a few SMPS's and the DLVC (DSP) from hypex, hope you remembered the VAT is 21% from there.

I was planning on going the UcD route with a 6 Channel set up for my active speakers.
I have since come down to 4 channels by keeping the passive element for Mid/Twt and I started looking at NCore options.

Hypex do an NC400 monoblock kit, which includes everything needed, including the case, binding posts etc, you only have to assemble it. It works out quite expensive and if you look at the fully assembled Hypex based stuff from Nord Acoustics (UK), there is not that much difference in price. Nord use the superior NC500 OEM modules and you get a finished product that's tested and has a warranty.

I know you mentioned wanting to get your hands dirty with a project, but I would seriously consider some of Nords lower end products. They use the NCxxxMP OEM modules, which have x2 Ncore amps on the PCB and share a common SMPS also on the same compact PCB/heatsink. I'm going to hear an 8 Channel 500w model later in the week, its by Apollon Audio (Austria) but uses the same boards.

Check out something like this:
https://www.nordacoustics.co.uk/product-page/nord-one-mp-nc250-stereo-power-amp

It's more than you were looking at spending, but it's a lot of amp for the money.

[r100]

This was his the list in order of preference, but now he says the Sure is on top.
Obviously this is just one builders views but there seems to be a lot of support for the Sure.

1. Hypex UcD2K Click the image to open in full size. ( Absolute Reference ).
2. Abletec ALC0300-1300 Click the image to open in full size. ( sound-quality wise very close to UcD2K ).
3. Hypex NC-400 Click the image to open in full size. ( Price / Performance-ratio ).
4. Abletec ALC1000-1300 Click the image to open in full size. Click the image to open in full size. ( extremley dynamic, might therefore lack long-term enjoyability on certain speakers ).
5. Connexelectronic CxD500 / SMPS600RE Click the image to open in full size.
6. L-15/25D Click the image to open in full size. ( only if speaker matches ).
7. Hypex UcD180 HG Click the image to open in full size.
8. Connexelectronic IRS2092 (500 + 700 Watt Stereo-Module).
9. Connexelectronic Tripath TA3020 / SMPS1000A Click the image to open in full size. ( unobtrusive ).
10. Hypex UcD400 HxR Click the image to open in full size. ( never really could convinve me ).
11. Hifimediy T2 Click the image to open in full size. ( good, well-sounding and inexpensive entry-level amp )
99. Hifimediy T3S Click the image to open in full size. ( absolutely not noteworthy ).

No. 6 are LJM L15/25 boards like these (https://www.aliexpress.com/item/Finished-LJM-L25D-HiFi-Audio-Stereo-Power-Amplifier-With-Speaker-Protection-AMP/32819699094.html?spm=2114.10010108.1000015.9.59d02 177abfmsx) (shown in a complete assembly with 2 L25D boards, rectifier, transformer, speaker protection, chassis, pot). And a version in kit form from here (https://www.aliexpress.com/item/New-amplifier-DIY-L25D-Power-amplifier-board-box-transformer-PSU-Protection/32808269010.html?spm=2114.10010108.1000014.7.52114 dc41s8l0W&traffic_analysisId=recommend_3035_4_83054_iswinsto re&scm=1007.13338.83054.0&pvid=d500cb13-4bc7-4ff6-83e2-e4f007a9b2e1&tpp=1). But you'll have to drill some holes :-)

[Shovel_Knight]

No. 6 are LJM L15/25 boards like these (https://www.aliexpress.com/item/Finished-LJM-L25D-HiFi-Audio-Stereo-Power-Amplifier-With-Speaker-Protection-AMP/32819699094.html?spm=2114.10010108.1000015.9.59d02 177abfmsx) (shown in a complete assembly with 2 L25D boards, rectifier, transformer, speaker protection, chassis, pot). And a version in kit form from here (https://www.aliexpress.com/item/New-amplifier-DIY-L25D-Power-amplifier-board-box-transformer-PSU-Protection/32808269010.html?spm=2114.10010108.1000014.7.52114 dc41s8l0W&traffic_analysisId=recommend_3035_4_83054_iswinsto re&scm=1007.13338.83054.0&pvid=d500cb13-4bc7-4ff6-83e2-e4f007a9b2e1&tpp=1). But you'll have to drill some holes :-)
The only question is: how do I know in advance if my speakers match the amplifier? :D

[r100]

yeah, I was thinking the same :eyebrows:

[Shovel_Knight]

Truth be told, I’ve already settled on building a Hypex amp. I will finalize the BOMs and share them here because they’re likely to be useful to others :-)

[r100]

This thread has gotten me interested in a new build... so after having read some reviews, I might put a pair of these (Anaview ALC 0300) into a chassis .. compared to the Hypex nCore N400, they seem to be quite a bargain, especially considering that the PS is built-in. A little more research needed though. Also, not sure where to get them as they are OEM.

https://www.eltim.eu/index.php?action=article&aid=7753&group_id=10000200&lang=en


https://images.reverb.com/image/upload/s--2U9kROeI--/a_exif,c_limit,e_unsharp_mask:80,f_auto,fl_progres sive,g_south,h_620,q_90,w_620/v1457541257/r7yninoa4w0zhalkuebz.jpg

[Shovel_Knight]

This thread has gotten me interested in a new build... so after having read some reviews, I might put a pair of these (Anaview ALC 0300) into a chassis .. compared to the Hypex nCore N400, they seem to be quite a bargain. A little more research needed though.


https://images.reverb.com/image/upload/s--2U9kROeI--/a_exif,c_limit,e_unsharp_mask:80,f_auto,fl_progres sive,g_south,h_620,q_90,w_620/v1457541257/r7yninoa4w0zhalkuebz.jpg

Where did you get them, if you don’t mind me asking? I can’t find them anywhere :-(

[r100]

A quick search yielded the below link. But I don't know the vendor.. just wanted an idea of the price range.

https://www.eltim.eu/index.php?actio...000200&lang=en (https://www.eltim.eu/index.php?action=article&aid=7753&group_id=10000200&lang=en)

this vendor seems to be "official"

http://www.lautsprechershop.de/hifi/anaview_uebersicht_en.htm#str-alc0100-2200

[Shovel_Knight]

This is a well-known supplier, I think they are based in Germany.

It’s a pity they have only one ALC0300 in stock (it’s a mono module).

[r100]

interesting amp with ncore modules, ready built and not much more than a diy kit

http://www.apollonaudio.com/apollon-amplifiers/

http://www.apollonaudio.com/wp-content/uploads/2017/12/NCMP4353W-Hypex-Based-Class-D-Multichannel-Amplifier-Inside-Modules-NC502MP-Frontpanel.jpg

[Qwin]

I heard the 8 channel Apollon today it was using the NC502MP Hypex modules (x4) and powering Linkwitz LX521 active speakers.
Very impressive dynamic sound with no background noise at all.

[oceanobsession]

I purchased an img stage line sta 800d 2x hypex 400 moduels and separate power supplies also by hypex £300 , I was only going to use it on the bass speaker but tried it running the whole system , sounded terrible to my ears , but it was ok on bass , hattor audio puts an integrated up for sale
on ebay about once a month and it goes for about £1200 , this has hypex components and n core powewr modules , me phil.

[r100]

Anyone here have a Hattor ? those are beautiful builds. The only thing I'm not a fan of are the fans on the sides.

[Shovel_Knight]

[rant mode on]

After doing some more research I have found that Abletec / Anaview amplifiers are ranked higher than Hypex UcD. However, after studying the available pictures and documents, I'm afraid I'm not going to use them, because they're using crappy capacitors. If you search for Anaview AMS1000/AMS0100 in Google images, you'll see that they're using CapXon caps in the switch power supply and JH caps elsewhere.

I have also found that Hypex uses Su'scon capacitors in their PSUs.

Call me paranoid, but I'm very suspicious of those capacitors, and for a good reason (I think). When I worked in tech support in a telecom company, we bought and installed several hundreds routers by two well respected companies. All these routers started going bad roughly 4-5 months after their warranty expired.

When we examined them, we discovered that those routers were using Su'scon caps for power filtering. Literally every single one of those capacitors failed.

Later we had a problem with brand name flat panel screens in the company's office which also started dying at the same time. Those had JH capacitors in their power supplies. NAD used JH capacitors in some of their low budget amps and guess what? They are also failing because the capacitors are going bad.

I really don't want to build an amp that will fail in a couple of years :steam:

[rant mode off]